The tissue core will continue to provide all SPORE investigators with appropriate tissue. This will include archival and prospective formalin- fixed, paraffin-embedded, benign and malignant breast tissue from patients with and without diagnosis of breast cancer. A special effort will be done to identify benign and hyperplastic tissue in patients who subsequently developed breast cancer. In addition, initial and subsequent tissues from patients with carcinoma in situ who developed recurrent disease. Prospective fresh and frozen benign and malignant breast tissue, as well as skin from patients with new breast cancer, will be collected. We expect to continue to collect prospective fresh tissues at the current rate of about 100 cases per year. We expect to continue to identify archival paraffin embedded cases of benign tissue, hyperplasia, carcinoma in situ, as well as invasive cancers with the specific characteristics needed by the various research projects. Sources for tissues are California Pacific Medical Center (CPMC) and Aeron Laboratories. CPMC has a bank of about 14,000 benign and malignant archival cases and receives approximately 300 new breast cancers every year. Aeron Laboratories performs hormone receptor analyses on breast cancer specimens and has through Dr. Dollbaum, who is medical director, made surplus frozen material available from about 15,000 specimens. The tissue utilization committee will continue to consider requests both from SPORE projects and outside investigators.